okay ill try xatu
EDIT: scarf gensect can flame it to death thanks for the help thought guys
Not really. +2 Mach Punch from Technician Breloom (the standard is Spore / Swords Dance / Mach Punch / Bullet Seed) does 103% mimum to 0 HP / 0 Def Genesect with a neutral nature, so that's a guaranteed KO even without Stealth Rock. Even Choice Band sets mess up Genesect, as Gensect is OHKOed by Superpower, or even Drain Punch after Stealth Rock.
There are several good Breloom checks though, bar Xatu. Note that for all of the following, they can't absorb Spore unless mentioned otherwise, so keep that in mind:
Chandelure is immune to Mach Punch and resists Bullet Seed, while it outspeeds, traps and OHKOes Breloom with Fire Blast. However, if Bullet Seed hits five times, Chandelure is OHKOed, and also risks being KOed by four hits in a row if Stealth Rock is up.
Dragonite is an excellent counter to Breloom, as it isn't even KOed by a +2 Bullet Seed that hits five times, even after Stealth Rock. It also outspeeds Breloom, and OHKOes with STAB Hurricane if you're using a rain team. Otherwise, Dragonite can use the following set very effectively:
Dragonite @ Lum Berry
Trait: Multiscale
EVs: 252 Atk / 4 Def / 252 Spe
Adamant Nature (+Atk, -SAtk)
- Dragon Dance
- Outrage
- Fire Punch
- ExtremeSpeed / Earthquake
Thanks to Lum Berry, Dragonite can safely switchin on every move, even Spore. Dragonite can Dragon Dance up, and OHKO Breloom with Outrage or Fire Punch. This set can easily sweep many teams, though I advice you pair this with a Rapid Spinner to keep Stealth Rock intact.
Good luck!